This invention pertains to a method and apparatus for performing soil percolation tests for determining the water absorption characteristics of soil.
The water absorption or percolation characteristics of soil are very important in determining the uses to which land can be put. That is, the erection of any structure on a plot of land causes water run-off due to the elements as well as water run-off from a septic tank or the like, if such is provided. The percolation characteristics of soil varies widely, and it is important to know what the percolation characteristics are of a given piece of land prior to erecting any structure on it. The soil has to be such that it can absorb the water run-off, else the structure should not be built. Many governmental organizations charged with land use and zoning responsibility in fact require a test of such percolation characteristics as a prerequisite of obtaining a building permit.
In the past, soil percolation tests have been performed by augering a test opening in the ground to a predetermined depth, and then filling the test opening with water to a predetermined depth, i.e., 12 inches. After a predetermined time, such as 10 minutes, the drop in water level is measured by manually inserting a ruler in the test opening and estimating the amount by which the water level has dropped. Then the water level is brought back up to its original level by pouring more water in the opening so as to perform additional absorption measurements. If this is not very carefully done, soil from the sides of the opening can be dislodged by the water and fall into the opening, causing errors and distortions in the percolation tests.
This prior percolation test technique did not produce consistent and accurate test results because it is necessarily dependent upon the person making the measurements, and subject to many errors in the way a ruler is inserted into the test opening, trying to read the water level from the ruler down in the opening, etc.